The Formal Syntax of Algernon

  

Notation:

x

denotes zero or more repetitions of x.

x

denotes one or more repetitions of x.

Also, the teletype font, font, is used for terminals (i.e., strings which actually occur in Algernon code).

 path                 =  (form  )

 rule             		= 		(form   <- form  )   

     				(form   -> form  )

 form             = predicate   

     				(:rules  term rule  )   

     				(:srules term rule  )   

     				(:del-rule term rule)   

     				(:del-srule term rule)   

     				(:del-rules term slot)   

     				(:del-srules term slot)   

     				(:contra-positive form  )   

     				(:wo-contra-positive form  )   

     				(:in-own-partition form)   

     				(:no-completion form)   

     				(:the  variable form  )   

     				(:the  (variable  ) form  )   

     				(:forc variable form  )   

     				(:forc (variable  ) form  )   

     				(:unp form  )   

     				(:all-paths path path)   

     				(:assume predicate)   

     				(:retrieve predicate)   

     				(:ask predicate)   

     				(:create variable atom  )   

     				(:show term)   

     				(:delete predicate)   

     				(:clear-slot term slot)   

     				(:decl-slots (slot number)  )   

     				(:slot atom (term  ) descriptor  )   

     				(:test expression)   

     				(:lisp expression)   

     				(:bind variable expression)   

     				(:bind-to-values variable term slot)   

     				(:branch-on-values variable expression)   

     				(:apply function expression)   

     				(:neq term term)

     				(:taxonomy set-descriptor)

 predicate  = (slot term term  )    (not predicate)

 term   = variable   

     				frame   

     				(slot term)   

     				(:slot slot)   

     				(:quote expression)

 descriptor  = T:cardinality number   

     				:partition term   

     				:backlink slot   

     				:inverse slot   

     				:comment string

 set-descriptor  = (term set-descriptor   term  )

 frame   = Any Lisp atom which is a name of a frame in the knowledge-base.

 slot   = Any Lisp atom declared as a slot in the knowledge-base.

 variable  = Any Lisp atom whose print name begins with a '?'.

 number   = Any number.

 string   = Any Lisp string.

 expression  = Any Lisp expression.

 atom   = Any Lisp atom.

 function  =  Any Lisp function (in a form suitable to be passed to the Lisp
function apply).